The charges are overblown, but also effective. And now that the presidential race is at stake, the Medicare messaging battle is bound to get a lot more brutal.

Perhaps the most illustrative example of these attacks is the infamous "granny-over-a-cliff" ad, from the liberal outside interest group The Agenda Project. The ad features a young man — who doesn't look unlike Paul Ryan — pushing an elderly woman in a wheelchair along a wooded path to the tune of "America The Beautiful." After a brief stroll, he pushes her off a cliff.

It ends with the tagline: "Is America beautiful without Medicare? Ask Paul Ryan and his friends in Congress."